Once viewed as a complex therapy with a significant degree of patient morbidity, guided bone regeneration (GBR) has become a predictable and relatively atraumatic procedure. This evolution has transformed the field of oral implant reconstructive therapy. Adequate bone may be predictably regenerated to ensure ideal implant positioning to provide the necessary bone to withstand functional forces over time and to positively impact aesthetic treatment outcomes. Despite these facts, clinicians still accept less than ideal GBR treatment results and continue to place implants at compromised positions and angulations.
This article will focus upon the prerequisites for maximization of GBR treatment outcomes, as well as presenting a more demanding definition of success following GBR therapy.
Soft-Tissue Primary Closure
The maintenance of soft-tissue primary closure throughout the course of bone regeneration is crucial. Failure to maintain such primary closures results in a lesser volume of regenerated bone, a lesser degree of predictability regarding the morphology of the regenerated bone, and a thinner covering of soft tissues, which, in turn, negatively impact aesthetic treatment outcomes.
Fortunately, proven flap designs ensure the maintenance of soft-tissue primary closures. These flap designs include:
- the use of long vertical releasing incisions on the buccal and lingual/palatal aspects of the sites to be regenerated
- horizontal extensions of the vertical releasing incisions, and at their apical extent
- full-thickness reflections of mucoperiosteal flaps, including the areas beneath the horizontal incision extensions
The Rotated Palatal Pedicle
When the aforementioned flap designs are not adequate to provide sufficient flap mobility for attainment of passive primary closure, a rotated palatal pedicle flap is employed. Following flap reflection, an incision is made on the internal aspect of the palatal flap, approximately 3.0 to 4.0 mm from the base of the flap. The palatal flap is then dissected in a coronal direction, utilizing a tissue pick-up and a #15 blade. The net result is an extension of the length of the palatal flap by approximately 50% to 60%.
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| Figure 1. A patient presented with a non-space maintaining defect following the extraction of a maxillary central incisor. | Figure 2. Bone regenerative therapy was performed with particulate material and a resorbable membrane. Note the non-ideal alveolar crest ridge form. |
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| Figure 3. A patient presented with a non-space maintaining defect following the extraction of a maxillary central incisor. | Figure 4. An ideal alveolar ridge form was re-attained following therapy with a particular material and a titanium reinforced membrane. |
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| Figure 5. The patient presented with significant atrophy due to the maxillary central incisors having been missing for many years. | Figure 6. Regenerative therapy was performed with particulate material and a detaining reinforced membrane. Note the ideal ridge form attained. |
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| Figure 7. A patient presented with severe ridge atrophy in the mandibular left posterior area. | Figure 8. Following regenerative therapy with particulate material in a titanium reinforced membrane, an ideal ridge form was regenerated. |
The Everted Flap
In specific situations, soft-tissue pedicles may be procured from within the extraction socket as well. When the buccal alveolar plate has been lost, and the socket has epithelialized, the everted flap approach is employed.
Material Selection
Confidence in the ability to maintain soft-tissue primary closure throughout the course of regeneration allows the clinician to choose the appropriate regenerative materials based on defect morphology, rather than therapeutic limitations. The importance of such selection criteria is evident when deciding between a resorbable or titanium reinforced covering membrane in a given situation.
Clinical Examples
A patient presented with significant osseous loss following the removal of a maxillary central incisor. The buccal wall of alveolar bone was missing, and the residual alveolar defect was non-space maintaining (Figure 1). Six months following the use of particulate material and a resorbable covering membrane, reentry demonstrated a less than ideal bone regenerative result (Figure 2). While significant bone regeneration had occurred, the alveolar bone at the crest of the ridge was thin and sloped. As a result, thin and labile peri-implant crestal bone would be present following implant placement. The stability of such bone under function over time is not predictable.
The definition of success following GBR therapy is one that demands a minimum of 2.0 mm of crestal bone buccally and palatally/lingually after implant placement and of such a morphology as to help support the soft tissues, thus maximizing both the functional and aesthetic treatment outcomes.
Another patient presented with a lack of buccal alveolar bone following the loss of the maxillary central incisor (Figure 3). The same particulate graft was utilized as in the previous case. However, the graft material was covered with a titanium reinforced membrane. A 6-month reentry demonstrated the regeneration of an ideal ridge form (Figure 4). As a result, following implant placement, thick peri-implant crestal bone was present, which can more predictably withstand functional forces over time.
When treating an area where a tooth is missing and a significant ridge atrophy has occurred, the use of titanium reinforced membrane and particulate material, in conjunction with the maintenance of soft-tissue primary closure for the 6 months of regeneration, results in an ideal ridge form (Figures 5 and 6). An implant may now be ideally positioned while still maintaining adequate crestal bone to withstand function over time.
In another example, rather than place an implant in thin and atrophic mandibular posterior bone, particulate materials and a titanium reinforced membrane were employed to regenerate ideal ridge contours in anticipation of implant placement (Figures 7 and 8).
CONCLUSION
When carried out appropriately following an insightful diagnosis and comprehensive treatment plan, guided bone regeneration allows conscientious clinicians to attain previously undreamt-of treatment outcomes.
Dr. Fugazzotto received his DDS from New York University in 1979 and a certificate in advanced graduate studies in periodontology from Boston University in 1981. Since that time, he has maintained a private practice in periodontics and implant therapy in Milton, Mass. Dr. Fugazzotto has authored or co-authored more than 90 articles in refereed scientific journals; a monograph entitled “Guided Tissue Regeneration: Maximizing Clinical Results;” and 3 textbooks, including Decision Making in Regenerative and Implant Therapies and Periodontal Restorative Interrelationships: Maximizing Treatment Outcomes. He is an active member of many organizations and a Fellow of the International Team of Implantology (ITI). Dr. Fugazzotto is senior editor of Implant Realities and the past US ITI Study Club Coordinator. He is a visiting lecturer at the Harvard University and Tuft University schools of dental medicine and lectures nationally and internationally on a multitude of topics. He can be reached at fugazzotto-rost.com.
Disclosure: Dr. Fugazzotto reports no disclosures.
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